Identification of susceptibility loci for Takayasu arteritis through a large multi-ancestral genome-wide association study.

Takayasu arteritis is a rare inflammatory disease of large arteries. We performed a genetic study in Takayasu arteritis comprising 6,670 individuals (1,226 affected individuals) from five different populations. We discovered HLA risk factors and four non-HLA susceptibility loci in VPS8, SVEP1, CFL2, and chr13q21 and reinforced IL12B, PTK2B, and chr21q22 as robust susceptibility loci shared across ancestries. Functional analysis proposed plausible underlying disease mechanisms and pinpointed ETS2 as a potential causal gene for chr21q22 association. We also identified >60 candidate loci with suggestive association (p < 5 × 10-5) and devised a genetic risk score for Takayasu arteritis. Takayasu arteritis was compared to hundreds of other traits, revealing the closest genetic relatedness to inflammatory bowel disease. Epigenetic patterns within risk loci suggest roles for monocytes and B cells in Takayasu arteritis. This work enhances understanding of the genetic basis and pathophysiology of Takayasu arteritis and provides clues for potential new therapeutic targets.

Identification of Susceptibility Loci in IL6, RPS9/LILRB3, and an Intergenic Locus on Chromosome 21q22 in Takayasu Arteritis in a Genome-Wide Association Study.

OBJECTIVE: Takayasu arteritis is a rare large vessel vasculitis with incompletely understood etiology. This study was undertaken to perform the first unbiased genome-wide association analysis of Takayasu arteritis. METHODS: Two independent cohorts of patients with Takayasu arteritis from Turkey and North America were included in our study. The Turkish cohort consisted of 559 patients and 489 controls, and the North American cohort consisted of 134 patients and 1,047 controls of European ancestry. Genotyping was performed using the Omni1-Quad and Omni2.5 genotyping arrays. Genotyping data were subjected to rigorous quality control measures and subsequently analyzed to discover genetic susceptibility loci for Takayasu arteritis. RESULTS: We identified genetic susceptibility loci for Takayasu arteritis with a genome-wide level of significance in IL6 (rs2069837) (odds ratio [OR] 2.07, P = 6.70 × 10(-9)), RPS9/LILRB3 (rs11666543) (OR 1.65, P = 2.34 × 10(-8)), and an intergenic locus on chromosome 21q22 (rs2836878) (OR 1.79, P = 3.62 × 10(-10)). The genetic susceptibility locus in RPS9/LILRB3 lies within the leukocyte receptor complex gene cluster on chromosome 19q13.4, and the disease risk variant in this locus correlates with reduced expression of multiple genes including the inhibitory leukocyte immunoglobulin-like receptor gene LILRB3 (P = 2.29 × 10(-8)). In addition, we identified candidate susceptibility genes with suggestive levels of association (P < 1 × 10(-5)) with Takayasu arteritis, including PCSK5, LILRA3, PPM1G/NRBP1, and PTK2B. CONCLUSION: Our findings indicate novel genetic susceptibility loci for Takayasu arteritis and uncover potentially important aspects of the pathophysiology of this form of vasculitis.

A novel recessive 15-hydroxyprostaglandin dehydrogenase mutation in a family with primary hypertrophic osteoarthropathy.

We present two PHO siblings having a novel homozygous truncating mutation in HPGD. The purpose of the study was to attempt medical treatment, and to find the HPGD mutation causing the disease, in a 22-year old Turkish male and his 23-year old sister afflicted with primary hypertrophic osteoarthropathy (PHO). In combination with NSAIDs and colchicine, treatment with sulfasalazine was started in both cases, and methotrexate was added to the treatment regimen of the female patient at the end of the first year. The patients were found to be typical PHO. Ultrasonographic examination of the joints revealed synovitis and inflammation by B mode and power Doppler ultrasonography. Joint symptoms responded to sulfasalazine treatment in both patients. However, after the addition of methotrexate, the female patient had better remission. All exons of HPGD, the known disease gene, were analyzed by Sanger sequencing. A homozygous 2-bp deletion (c.310_311delCT or p.L104AfsX3) was identified. Seven relatives carrying the mutation in the heterozygous state were examined and none was found affected. Although not specific for this disease, skin, soft tissue and joint ultrasonography can be helpful for evaluation of the musculoskeletal findings in the patients.

Serum eosinophil cationic protein levels in Behçet's disease and its relation to clinical activity.

BACKGROUND: Eosinophil cationic protein (ECP) is a matrix protein of eosinophils and has been reported to reflect eosinophil activity. Few studies have examined the role of eosinophils in the pathogenesis of Behçet's disease. OBJECTIVE: The purpose of the present study was to investigate the serum ECP levels in BD and its relation to clinical activity. METHODS: Forty-seven consecutive patients with BD (22 active, 25 inactive), 21 age and sex matched patients with allergic rhinitis and 21 healthy controls were evaluated cross-sectionally. The serum ECP levels were measured by the flourescein enzyme immunoassay method. RESULTS: Mean serum ECP levels of active patients with BD (34.28 ± 23.43 µg/L) were found to be significantly lower than those of the inactive patients (65.69 ± 46.32 µg/L, p <0.05) and the controls (62.92 ± 30.49 µg/L, p <0.01) . Behçet patients with oral aphthous lesions had significantly lower mean serum ECP levels (n=21, 38.82 ± 33.38 µg/L) than those without aphthous lesions (n=26, 60.81 ± 43.21µg/L) (p = 0.041). Similarly patients with arthritis had lower serum ECP values (n=6, 22.12 ± 9.47 µg/L) than those without arthritis (n = 41, 55.21 ± 41.35 µg/L) (p =0.029). CONCLUSIONS: Lower ECP levels in the active phase of the disease may be a result of decreased production due to the activation of Th1 cytokines.

PDCD1 polymorphisms are not associated with Takayasu's arteritis in Turkey.

OBJECTIVES: Takayasu's arteritis (TA) is a chronic arterial inflammation of unknown etiology involving mainly the aorta and its major branches. Based on the associations of programmed death-1 (PD-1) protein encoding gene (PDCD1) with connective tissue diseases and vasculitides, PDCD1 polymorphisms are studied for susceptibility to TA in this study. METHODS: The study group is made up of TA patients (n=229) fulfilling the 1990 ACR classification criteria and compared to 193 healthy controls (HC). PD-1.3, PD-1.5 and PD-1.6 single nucleotide polymorphisms of PDCD1 gene are genotyped by polymerase chain reaction and restriction analysis (PCR-RFLP). RESULTS: The distribution of PD-1.5 polymorphism in TA patients and HC revealed a similar presence of TT genotype in patients and controls (13.3% vs. 11.4%). PD-1.3 and PD-1.6 were less polymorphic and did not differ between the groups. Rare AA genotype of PD-1.3 (1.4% vs. 1.0%) and AG genotype of PD-1.6 was again similarly (22.4% vs. 19.2%) present in TA and HC. CONCLUSIONS: PD-1.3, 1.5 and 1.6 polymorphisms of PDCD1 gene, which were shown to be associated with various autoimmune disorders and vasculitides, are not associated with a susceptibility to TA in Turkish population.

Investigation of C5a receptor gene 450 C/T polymorphism in Turkish patients with familial Mediterranean fever.

Familial Mediterranean fever (FMF) is a genetic disorder with acute inflammatory serosal attacks due to MEFV gene mutations which resides in chromosome 16. Lack of a C5a inhibitor activity in the peritoneum has previously been proposed in part to contribute in propagation of the serosal inflammation in FMF attacks. The aim of this study is to investigate C5a receptor (C5aR) gene polymorphism in patients with FMF and its relation to the main features of the disease. A polymorphism in the coding region of C5aR gene leading to C to T transition at nucleotide position 450 has been investigated in 85 non-related Turkish FMF patients and 160 non-related healthy controls by using PCR-RFLP. The frequencies of C5aR gene 450 CT genotype and T allele were not significantly different between Turkish FMF patients and healthy subjects (14.12 and 8.24% for FMF vs. 10 and 5% for controls, respectively). C5aR gene 450 CT genotype tended to associate with the presence Henoch-Schonlein purpura (OR: 1.25, 95% CI: 0.917-1.704, P = 0.017) but with no other clinical findings of the disease. C5aR polymorphism might be searched in populations having high prevalence of FMF.

Reactive arthritis due to zoophilic (canine) sexual intercourse.

Reactive arthritis (ReA) is defined as a joint inflammation triggered by a distant infection, with no cultivable microbes in the joints. Although efforts have been made to characterize the microorganism linked to ReA, no definite common feature has so far emerged. Here we present a case of ReA which occurred after a zoophilic (canine genus) sexual intercourse.

Evaluation of the Turkish version of the Bath Ankylosing Spondylitis Patient Global Score (BAS-G).

The objective of this study was to investigate the reliability and validity of the Turkish version of the Bath Ankylosing Spondylitis (AS) Patient Global Score (BAS-G). Seventy-one consecutive patients with AS were enrolled into the study. Patients were requested to fill in the questionnaire on the day of admission (first visit), on a second occasion within 24 h after admission (second visit) for test-retest reliability analysis, and on a third occasion for assessing sensitivity to change. Construct validity was assessed by correlation analysis with the Bath AS Functional Index (BASFI), Dougados Functional Index (DFI), Dougados Articular Index (DAI), physical examination findings, and several other parameters. Test-retest reliability analysis of individual BAS-G scores at initial and second visits showed good intraclass correlations [n=46, intraclass correlation=0.928 (0.870-0.960) and intraclass correlation=0.853 (0.725-0.920), for 1-week and 6-month scores, respectively]. Both 1-week and 6-month scores showed moderate correlations with the BASFI (r=0.586 and r=0.503, respectively, P=0.000 for both). The 1-week score also showed moderate correlation with the DFI (r=0.530, P=0.000). The 1-week score showed weak correlations with finger-to-floor distance (r=0.263, P=0.027), chest expansion (r=-0.245, P=0.039), and DAI (r=0.271, P=0.036). Change in the 1-week score at the third visit showed good correlation with the BASFI score (r=0.670, P=0.000, n=36) and moderate correlation with the DFI (r=0.440, P=0.017, n=29). The Turkish version of the BAS-G has good reliability and validity. It is a good tool for assessing patients with AS or other rheumatic diseases in clinical practice and research.

Plasma interleukin-10 and interleukin-12 levels in patients with familial Mediterranean fever.

Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by recurrent attacks of fever, polyserositis and arthritis. A vast array of cytokines were analysed in these patients, however, little is known about the pro-inflammatory cytokine interleukin (IL)-12. Plasma IL-12 and IL-10 were measured in 24 patients with FMF (19 active, 5 inactive) and 18 healthy controls by ELISA. From 15 active patients blood was also drawn in attack-free period. Mean plasma IL-12 levels of the FMF patients (mean +/- SEM, 6.84+/-3.59 pg/ml) were higher than the controls (0.13+/-0.09 pg/ml, P < 0.001). Mean IL-12 levels of active (7.02+/-5.23 pg/ml) and inactive patients (6.89+/-5.61 pg/ml) were comparable, and they were higher compared to controls (P < or = 0.001). Mean plasma IL-10 levels of the total FMF patients (3.01+/-1.53 pg/ml) were also higher than the controls (P = 0.024). Patients had higher IL-10 levels in attacks (3.83+/-2.02 pg/ml) compared to levels when they were in remission (1.86+/-1.59 pg/ml, P = 0.046). Significantly elevated IL-12 levels in FMF patients regardless of activity may suggest the presence of a pro-inflammatory state also in the inactive period of FMF. Significant increase in IL-10 levels in FMF group may point to the compensatory suppression of inflammation in active periods of the disease.

Comparison of amplification refractory mutation system and polymerase chain reaction-restriction fragment length polymorphism techniques used for the investigation of MEFV gene exon 10 point mutations in familial Mediterranean fever patients living in Cukurova region (Turkey).

Familial Mediterranean fever (FMF) is an autosomal recessive inherited disease characterized by recurrent fever, serositis and arthritis. The disease is highly prevalent in Mediterranean basin populations. Recently, the gene responsible for FMF (MEFV) was cloned and at least 40 MEFV gene mutations have been identified. The most frequently observed mutations in the MEFV gene are M694V, M694I, M680I, and V726A. These occur within exon 10 of the gene, and account for 85% of the known MEFV alleles. In this study, the reliability and economical aspects of amplification refractory mutation system (ARMS) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques were compared for analyzing the frequencies of the major point mutations of 90 unrelated patients with FMF from the Cukurova region in Turkey. Both techniques yielded similar results: The ratio of independent alleles of 90 patients carrying one of the tested mutations was 81.1%; patients consisted of 12 different genotypes. In 64 of 90 patients (71.1%) mutations were observed in both alleles. Thirty-six patients (40%) were homozygous for the same mutation, 28 (31.1%) were heterozygous for different mutations. Eighteen patients (20%) were heterozygous for one allele with one of the four mutations but the other allele was unknown. In 8 patients (8.8%) no mutation could be detected. The most frequently observed mutation was M694V (51.66%), followed by M680I (17.22%), V726A (10.55%), and M694I (1.66%). In conclusion ARMS and PCR-RFLP techniques were equally reliable to detect the mutations in Turkish FMF patients. However, the ARMS technique was found to be more rapid and economical than the PCR-RFLP techniques.

Skewed X chromosome inactivation in blood cells of women with scleroderma.

OBJECTIVE: Scleroderma (SSc) is an autoimmune disease of unknown etiology. The disease is 3-8 times more frequent in women than in men. The role of X chromosome inactivation (XCI) in the predisposition of women to autoimmunity has been questioned. Until now this has not been illustrated experimentally. This study was undertaken to test the hypothesis that disturbances in XCI mosaicism may be involved in the pathogenesis of the disease in female patients with SSc. METHODS: Seventy female SSc patients and 160 female controls were analyzed for the androgen receptor locus by the Hpa II/polymerase chain reaction assay to assess XCI patterns in DNA extracted from peripheral blood cells. Furthermore, skin biopsy samples were obtained from 5 patients whose blood revealed an extremely skewed pattern of XCI, and the analysis repeated. Since microchimerism in SSc was reported, Y chromosome sequences were investigated in all samples. RESULTS: Skewed XCI was observed in DNA from peripheral blood cells in 35 of 55 informative patients (64%), as compared with 10 of 124 informative controls (8%) (P < 0.0001). Extreme skewing was present in 27 of the patient group (49%), as compared with only 3 of the controls (2.4%) (P < 0.0001). However, XCI was random in all skin biopsy samples. The potential contribution of microchimerism to the random XCI pattern is highly unlikely based on the medical histories of the patients. CONCLUSION: Skewed XCI mosaicism may play a significant role in the pathogenesis of SSc.

Evaluation of the Turkish version of the Dougados functional index in ankylosing spondylitis.

UNLABELLED: To investigate the reliability and validity of the Turkish version of the Dougados functional index (DFI) in patients with ankylosing spondylitis (AS). The Turkish version of DFI was obtained after a translation and back-translation process. Seventy consecutive patients with AS were enrolled. Patients were requested to complete the questionnaire on the day of admission (first visit), a second time within 24 h after admission (second visit), and on a third occasion. Reliability, validity and reproducibility of the Turkish version of the index were assessed. All the items showed significant correlations with the total index score with r-values ranging from 0.516 to 0.817. Cronbach alpha score was calculated as 0.908. Significant correlations were found between the total DFI score and Schober test (r=-0.293, P<0.05), occiput-wall distance (r=0.384; P<0.01) finger-to-floor distance (r=0.450, P<0.001), chest expansion (r=-0.331, P<0.01) and Dougados articular index (r=0.352, P<0.05). Good correlations were found between individual DFI items and the total score (r=between 0.533 and 0.882, p< 0.001) for the first and second visits, showing good reproducibility of the index. CONCLUSION: the Turkish version of DFI has good reliability, validity and reproducibility, confirming its utility for trials in Turkish AS patients.

The Turkish version of the Bath Ankylosing Spondylitis Functional Index: reliability and validity.

The purpose of this study was to investigate the reliability and validity of the Turkish version of the Bath Ankylosing Spondylitis (AS) Functional Index (BASFI). The Turkish version of the BASFI was obtained after a process of translation and back-translation. Eighty-one consecutive patients meeting the 1984 New York criteria for AS were enrolled. Patients were evaluated and requested to complete the questionnaire at days 1 and 2 and on a third occasion between days 15-90. Reliability, reproducibility, validity and sensitivity to change of the Turkish version of the index were assessed. Each score correlated closely with the index score, with coefficients between 0.727 and 0.844. Reliability analysis showed a Cronbach's alpha score of 0.926. Correlations were found between all items of the BASFI and Schober's test (r=-0.258 to -0.531, p<0.001-0.05), occiput-to-wall distance (r=0.284 and 0.589, p<0.001-0.05), and finger-to-floor distance (r=0.334 to 0.613, p<0.001-0.01). The total index score was correlated with the number of nocturnal awakenings (r=0.515, p<0.001), Schober's test (r=-0.444, p<0.001), finger-to-floor distance (r=0.567, p<0.001), occiput-to-wall distance (r=0.535, p<0.001), chest expansion (r=-0.403, p<0.001), and the Dougados articular index (r=0.371, p<0.01). A good correlation was found between day 0 and 1 BASFI indices (r=0.765-0.917, p<0.001), showing good reproducibility of the index. The Turkish version of the BASFI showed reliability, reproducibility, and validity, confirming its utility in the research of AS in Turkey. However, sensitivity to changes due to drug therapy and/or rehabilitation remains to be determined.

The association between cervical rib and sacralization.

STUDY DESIGN: After determining the normal reference values for the length of the transverse processes of the seventh cervical vertebra, the association between the presence of cervical rib and sacralization was investigated. OBJECTIVE: To determine the length of cervical rib and search for any association between cervical rib and sacralization. SUMMARY OF BACKGROUND DATA: Both cervical ribs and sacralization have been noted in some patients in the authors' clinical practice. METHODS: The cervical rib is a supernumerary rib arising from a cervical vertebra, or it might be simply an elongation of the transverse process of the seventh cervical vertebra. However, there is no consensus about a specified length of this process. For reference values, anteroposterior cervical radiographs of 210 normal individuals (112 male, 98 female, mean age 33.9 +/- 10.1 years, range 19-61 years) were taken, and elongation of the transverse processes beyond 2 standard deviations (30 mm) was considered as cervical rib. In the guide of the reference values, 324 outpatients (165 male, 159 female, mean age 42.0 +/- 14.6 years, range 17-85 years), having cervical ribs or sacralization detected by plain radiographs, were taken as the study group. As control 729 volunteers (364 male, 365 female, mean age 41.7 +/- 14.3 years, range 15-76 years) were studied. RESULTS: In 1053 patients, of 471 patients having cervical ribs, 345 (73.2%) had also sacralization; of 536 patients with sacralization, 345 (64.4%) also had cervical ribs. Significant associations were found between cervical rib with or without articulation and sacralization [chi2 = 52.284, P < 0.001, odds ratio 5.097 (3.156-8.234); chi2 = 139.473, P < 0.001, odds ratio 5.204 (3.922-6.905), respectively]. CONCLUSION: Presence of cervical rib might be a clue to the existence of sacralization or vice versa. In patients with cervical or lumbar pain, this association may be helpful for differential diagnosis before applying sophisticated diagnostic techniques.